U.S. Pat. No. 4,419,866, which is assigned to the same assignee as the present application, discloses a transport refrigeration system in which a Diesel engine which drives a refrigerant compressor may be selectively operated in continuous or start-stop modes. In the start-stop mode, the Diesel engine is under the control of a refrigeration thermostat, being stopped and re-started as the temperature of the refrigeration system enters and leaves predefined temperature bands relative to a selected temperature set point. While the control circuitry disclosed in the patent performs well, it would be desirable, and it is the object of the present invention, to simplify the control and improve the logic, without loss of required functions.